GLENDALE, Calif. – A Southern California school bus driver has been arrested after allegedly sexually assaulting a child and investigators believe there are other victims, police announced Wednesday.

Denis Alcazar is shown in a photo released by the Glendale Police Department on May 16, 2018.

Denis Alcazar, 34, of Los Angeles was arrested on May 2 on suspicion of false imprisonment and substantial sexual conduct with a child under 14, police said.

Glendale police began an investigation on Oct. 5, 2017, when they received a report about "inappropriate contact" between the alleged victim, who is a 4-year-old with special needs, and her school bus driver. The girl lives in Glendale, a city roughly 10 miles north of downtown Los Angeles.

The investigation led to another alleged victim in the city of Bell Gardens, some 20 miles south of Los Angeles. In that incident from five years ago, Alcazar allegedly sexually molested his girlfriend's daughter while he babysat her, police said. The daughter was also 4 years old at the time.

In a news release, police said they discovered "other victims from Los Angeles and Bell Gardens" but they did not elaborate on those cases. An email from Glendale police described Alcazar as a "man who allegedly sexually assaulted a child."

“I personally don't believe that this is going to be the first time this individual’s done this," Sgt. Dan Suttles said. "If he did it five years ago, and now he’s doing it again, there’s a long span in between. I fear that he’s out there victimizing other children.”

Alcazar was employed by the First Student Bus Co. at the time of the incident with the 4-year-old in Glendale, and he most recently worked for Brooks Transportation, police said. Both companies contract with school districts across Los Angeles County.

He remains in jail and his bail was set at $400,000. He is scheduled to appear in court on June 15.

Officials believe there may be more victims and ask anyone with information to call 818-548-3106.